libata: add another IRQ calls (core and headers)

This patch is against the libata core and headers.

Two IRQ calls are added in ata_port_operations.
- irq_on() is used to enable interrupts.
- irq_ack() is used to acknowledge a device interrupt.

In most drivers, ata_irq_on() and ata_irq_ack() are used for
irq_on and irq_ack respectively.

In some drivers (ex: ahci, sata_sil24) which cannot use them
as is, ata_dummy_irq_on() and ata_dummy_irq_ack() are used.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-sff.c

@@ -64,6 +64,46 @@ u8 ata_irq_on(struct ata_port *ap)
 	return tmp;
 }
 
+u8 ata_dummy_irq_on (struct ata_port *ap) 	{ return 0; }
+
+/**
+ *	ata_irq_ack - Acknowledge a device interrupt.
+ *	@ap: Port on which interrupts are enabled.
+ *
+ *	Wait up to 10 ms for legacy IDE device to become idle (BUSY
+ *	or BUSY+DRQ clear).  Obtain dma status and port status from
+ *	device.  Clear the interrupt.  Return port status.
+ *
+ *	LOCKING:
+ */
+
+u8 ata_irq_ack(struct ata_port *ap, unsigned int chk_drq)
+{
+	unsigned int bits = chk_drq ? ATA_BUSY | ATA_DRQ : ATA_BUSY;
+	u8 host_stat, post_stat, status;
+
+	status = ata_busy_wait(ap, bits, 1000);
+	if (status & bits)
+		if (ata_msg_err(ap))
+			printk(KERN_ERR "abnormal status 0x%X\n", status);
+
+	/* get controller status; clear intr, err bits */
+	host_stat = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
+	iowrite8(host_stat | ATA_DMA_INTR | ATA_DMA_ERR,
+		 ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
+
+	post_stat = ioread8(ap->ioaddr.bmdma_addr + ATA_DMA_STATUS);
+
+	if (ata_msg_intr(ap))
+		printk(KERN_INFO "%s: irq ack: host_stat 0x%X, new host_stat 0x%X, drv_stat 0x%X\n",
+			__FUNCTION__,
+			host_stat, post_stat, status);
+
+	return status;
+}
+
+u8 ata_dummy_irq_ack(struct ata_port *ap, unsigned int chk_drq) { return 0; }
+
 /**
  *	ata_tf_load - send taskfile registers to host controller
  *	@ap: Port to which output is sent
@@ -370,8 +410,7 @@ void ata_bmdma_thaw(struct ata_port *ap)
 	/* clear & re-enable interrupts */
 	ata_chk_status(ap);
 	ap->ops->irq_clear(ap);
-	if (ap->ioaddr.ctl_addr)	/* FIXME: hack. create a hook instead */
-		ata_irq_on(ap);
+	ap->ops->irq_on(ap);
 }
 
 /**